With the rapid popularization and a continuous increase in the network connection speed, mobile computing capability, and display quality, portable devices (mobile phones, tablet computers, and so on) have become a very good entertainment platform, and consumers spend more and more time on portable devices, for example, playing games and watching videos on portable devices.
The field of view (FOV) of a human eye vision system is about 180 degrees in a horizontal direction and about 135 degrees in a vertical direction. Generally speaking, larger coverage of display content in the FOV of a user brings the user a better immersive image viewing experience. Generally, the size of a display screen of the portable device is restricted by its portability, and therefore, the portable device can only cover a small part of the FOV of a user when being placed at a natural viewing position of the user, and it is difficult to provide an immersive image viewing experience. In addition, high-quality image content having an attribute such as high resolution and a large FOV cannot be adapted to a display screen of a portable device having a small FOV and low resolution, which affects a viewing experience of a user.